SU869889A1 - Method of automatic regulation of strip thickness - Google Patents

Description

The invention relates to the automation of production processes in the metallurgical industry and can be applied to cold rolling mills with a roll spanning field. The closest to the described method in terms of technical capacity and the achieved result is the method of automatic control of the strip thickness on the cold rolling-drawing reversing mill 1. The essence of this method consists in acting on the drives of the stand rolls with a resultant signal equal to the sum of signals proportional to the deviation of the strip thickness at the entrance and exit of the stand, i.e. in terms of the magnitude and polarity of the resultant signal (is the sum of the current deviations of the thickness at the entrance and exit of the cell), they form a signal for increasing or decreasing the exhaust H., where VB is the predetermined basic speed of the driving roll; set the base speed of the driven roll. The disadvantage of this method is that effective control of the thickness of the strip can be carried out at only one base rolling speed, which is determined by the speed of the driving roll. But at one base speed, rolling and adjusting the strip thickness is almost impossible, which is dictated by the features of the rolling technology of various grades of steel and alloys. In addition, the rolling cycle consists of acceleration (set speed from O to base), steady state (rolling at base speed) and deceleration (reduction of rolling speed from base to 0). And this means that in dynamics (during acceleration and deceleration), the efficiency of adjusting the thickness of the band C1 is shrunk. A decrease in the control efficiency is that when rolling at a speed higher than the baseline, there is underregulation, and when rolling at a speed lower than the baseline, the bandwidth is overshoot. This can be explained as follows. For example, we have a strip with a nominal thickness of 2.0 mm and a positive thickness variation, and hg 0.2 mm. The base rolling speed in the airfoil Vft is 4 m / s, nominal extraction, Yang 2.0. At a speed of Ve of 4 m / s, the nominal exhaust of Xi 2.0 can be provided at a speed of ff 2 m / s, i.e. 4m / s . A-and VB / VBO, 2.0 And in this case, the basic level of the velocity difference between the leading Vg and the driven Vfto of the rolls is iV5 Vgp 4 m / s - 2 d / s 2 m / s. When rolling a nominal thickness of a strip of h 2.0 mm with a nozzle exhaust of Hc 2.0, the output will have a nominal output thickness of 1.0 No. 4, since H IV .. When rolling a different thickness, the thickness of the strip N0 2.0 , 2 mm 2.2 mm, it is necessary to increase the exhaust flow in the passage, so that at the exit you also get the “current exhaust JL XHjtAX. . And equal to Е Н Н N W 1I Dn + D lO DX 0,2 and then V 2,2. In the case of simultaneous impact on the drive of the driving and driven rolls, the value of T 2.2 can be ensured by increasing the speed of the driving roll, for example, by 0.2 m / s and reducing the speed of the driven roll by m / s, then:

 V ,,

4DMGs

2.2 Now

  VBO 4.9 “/ c - increase the rolling speed Vftg Hume / s

In this case, when 1ts 2.0, U is 5 m / s and the current level is the difference of the speed of the driven driven rolls U V 5 m / s.

When rolling a strip with the same thickness, as in the first case, i.e. io Ldc + lkv 2.0 mm - 0.2 mm 2 mm, it is also necessary to provide 11 2.2, but the same signal will come to the drive of the drive roller,

FIG. 2 shows a block diagram of one of the embodiments of the described method.

Claims (1)

Graphic analysis (ig. L) showed. that npHuV. the underregulation zone expands with an increase in tM, and when the overshoot zone expands with a decrease in & V. This means that with increasing av it is necessary in more narrowly. increase the speed of the lead, f, and reduce the speed of the slave At the rolls, a portion of the increase in lf, by 0.2 m / s and a decrease in Uiv by 0.1 m / s. / - As a result, we will have iji - N60 iOj. 2.08. 5 m / s - O, I m / s 4.9 m / s and the current thickness at the exit is h 0 / .06. T.e, al1., - Hn 0.08. By reducing the rolling speed to V. 2 m / s. Yan 2.0 can be achieved at Vjjj 1 m / s. In this case, the current level of the speed difference of the master slave / roll 1 - 1 m / s. in this case, when rolling a strip with the same thickness variation, Vj will also increase by 0.2 m / s, and Vgo will decrease by O, 1 m / s, therefore l.OMic-o.gMic. g.iMtc. rr 4.0 MIC. -O.-IMIC 0, / 60 as a result, on the Bbixone stand we get the current thickness h i. K 3 VL A - IH 0.44. Thus, in the case where the current level of the difference is greater than the baseline (dU 5 m / s dU5 2 m / s), it becomes underregulated. strip thickness (h 1.06 mm V 7Hz 1.0 mm), and when the current difference level VgQ is less than the base (ftV "I m / s AV5 2 m / s), an overshoot of the strip thickness is obtained (h 0.9 mm N; , c 1.0 mm). FIG. 1 shows the grabik dependency: pavement on the level of speeds) and Veoi The graph shows the dependence of the stretch on the difference in speed. . Growth rolls and marked: 1- required value. Aj "f (V6i-eo) f (uV) 2 are valid values. LT f (U) f (& V) .. while decreasing & Y in narrower orders, increase the speed of the lead Vg and decrease the speed of the driven rolls than when rolled at the base (dUd) level of the difference between the speeds of the drive and driven rolls ( when rolling ke at base speed). Obviously, taking into account the foregoing, it is possible to improve the accuracy and efficiency of the strip thickness control, for which it is necessary to correct the resulting signal (with which the control over the drive and driven rolls are controlled) as a function of the difference between the base and current speed difference levels drive and driven rolls. The aim of the invention is to increase the productivity, the accuracy of the rolled strips, the decrease in the length of the sub-standard ends by increasing the efficiency of adjusting the thickness of the strip. The goal is achieved by additionally measuring the speeds of the driving and driven rolls, determining the current level of the speed difference between the driving and driven rolls by subtracting the speed of the driven roller from the driving speed, setting the base level of the speed difference between the driving and driven rolls, from the base level of speed difference leading and driven rolls subtract the current level of the difference between the speeds of the leading and driven rolls, and a signal proportional to the difference of the base and current levels, correct the resulting second signal equal to the sum signals which are proportional to the deviation of the thickness of the upstream and downstream stands. The signal from the thickness gauge 3 along: the rails installed in front of the cage are compared with the signal of the predetermined thickness of the rolled strip, the deviation signal of the rolled strip is fed to the input of the summation unit 4. The signal from the meter 5 strip thickness. Installed behind the cage ,. compared with the output thickness setting signal, a signal proportional to the deviation of the actual output thickness is fed to the input of the summation unit-4, as a result, a resulting signal is obtained at its output proportional to the sum of the deviations of the thickness at the entrance and exit of the cage. The signal from the speed sensor 6 of the driven roll in the comparison unit 7 is subtracted from the signal from the speed sensor 8 of the driving roll, resulting in a signal proportional to the current level of the difference between the speeds of the driving and driven rolls at the output of the comparison block 7. This signal is subtracted by the comparison block from the given value of the base level of the difference between the speeds of the driving and driven rolls and already depending on the polarity of the signal proportional to the difference between the basic and current levels of the difference of the speeds of the leading 1 and driven rolls in the converter 10, the signal proportional to the sum of the thickness deviations by the input and output of the stand, after which a signal proportional to the corrected signal is fed to the input II of the drive of the driving and driven rolls. The invention of the method of automatically adjusting the thickness of the strip by acting on the drives of the work rolls of the stand according to the deviation of the thickness of the strip at the entrance and exit of the stand, is due to the fact that, in order to increase productivity, the accuracy of rolled strips, reduce the length of substandard ends by increasing efficiency control, additionally measure the speeds of the driving and driven rolls, determine the current level of the speed difference between the driving and driven rolls, set the base level of the speed difference between depending on the assortment of the strip, the current level of the speed difference between the drive and driven rolls is subtracted from the base level of the speed difference between the drive and the driven rolls and the impact is corrected in proportion to this difference. Sources of information taken into account in the examination 1. USSR author's certificate 500842, cl. B 21 B 37/02, 1974. doffo  ff .0, ff, -%, / y / $ ffg.f / iff ffej ej eg / fyj ff ff / fffjf ff: jff A / ff j f / ffff / 77y. ff ifjfffff / 77 ff fff ff / yes / fff / 7 / ff / fKf